Pivoted ejector for earthmoving scrapers



SePt- 9, 1969 R. G. WAGNER PIVOTED EJECTOR FOR EARTHMOVING SCRAPERS Filed July 10, 1967 INVENTOR.

ROBERT G. WAGNER United States Patent: O

3,465,458 PIVOTED EJECTOR FOR EARTHMOVING SCRAPERS Robert G. Wagner, Tazewell, Ill., assignor to Caterpillar Tractor Co., Peoria, Ill., a corporation of California Filed July 10, 1967, Ser. No. 652,114 Int. Cl. E021? 3/ 76; B60p 1/00 U.S. Cl. 37-129 2 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Bulldozing ejectors are commonly employed in earthmoving Scrapers and, when it is desirable to unload the scraper bowl, the ejector is caused to forwardly traverse the scraper bowl to eject material therefrom. Such ejectors have 'been employed in a xed vertical position but they tend to ride up when their forward motion is resisted by material in the bowl and this results in undesirable stresses in the ejector assembly and possible binding of the ejector with the scraper bowl. Thus, a more commonly employed ejector assembly includes an ejector plate which inclines upwardly and rearwardly such that it tends to wedge under the load which reduces its tendency to ride up and over the material in the bowl. However, such inclined ejector plates are undesirable in that they reduce the load-carrying capacity of the bowl particularly adjacent the bowl oor. Thus, there is not only a possible reduction in the overall bowl capacity but also the load is carried higher in the bowl thus adding to the instability of the scraper particularly when it is of a type having a large load-carrying capacity. In addition, both the vertical and the inclined ejector plates, being fixed in those positions, encounter considerable resistance particularly during the rst few inches of ejection travel due to the necessity of setting all of the material in the bowl in motion simultaneously from a steady state condition.

SUMMARY OF THE INVENTION The present invention overcomes the above problems by providing an ejector plate which is pivoted at its base and which may assume a vertical position in the rear of the scraper bowl. Ejector means act upon the ejector plate generally adjacent its base to cause forward traversal of the scraper bowl by the ejector plate while limit means limit the pivoted motion of the ejector plate at a desirable preselected angle during traversal of the bowl.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a vertical longitudinal central sectional view of an earthmoving scraper showing the ejector assembly of the present invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Although the present invention is described with particular reference to an earthmoving scraper of a type which is loaded by forward motion of the scraper and which has a pivotal apron to retain the load, it will be readily apparent that the ejector assembly of the present invention can also be employed with other types of earthmoving ice Scrapers, for example, self-loading Scrapers which employ an elevator to assist in loading of the scraper bowl.

Referring now to the drawing, an earthmoving scraper 11 comprises a bowl 12 with its rear framework 13 supported by a pair of wheels, one of which is indicated at 14, and forwardly extending side arms (not shown) for connection to and support by a tractor (not shown). The scraper bowl has a pair of sidewalls, one indicated at 16, and a floor 17 with a cutting edge 18 disposed along the forward edge of the floor. An apron 19 is pivotally connected to each of the bowl sidewalls by a connection 21 and may be raised or lowered according to retraction or extension of a rod 22 pivotally connected to the apron at 23 and associated with a hydraulic jack (not shown). The apron is raised to permit loading and unloading of material over the cutting edge and is lowered to the position shown in the drawing to retain material in the bowl during transport.

The present invention provides an ejector plate 24 which is illustrated in its normal loading position at the rear of the scraper bowl. The ejector plate is pivotally connected at y 26 to an ejector carriage 27 and has a hydraulic jack 28 for exerting an ejection force upon the ejector plate, generally adjacent to the ejector plate base. Limit means 29 cooperate with the ejector plate causing it to assume a vertical position while at the rear of the scraper bowl while limiting its pivotal motion during forward traversal of the scraper bowl to a desired preselected angle illustrated at position 31 of the ejector plate.

The ejector carriage includes an elongated member at either side of the scraper, one being illustrated at 32, having a pair of rollers 33 disposed for rotation thereon. The rollers ride in a track 34 incorporated in the structure 13 extending rearwardly from the scraper bowl. The ejector plate is connected to each of the elongated members at the pivotal connection 26. The carriage also includes ejector support members, one of which is indicated at 36, and which are affixed to the elongated members 32 generally adjacent their pivotal connection with the ejector plate. Braces 37 hold the support members at the angle desired during forward traversal of the ejector through the bowl. Extensible means, for example the chain indicated at 38 in the drawing, are connected between the peak 39 of the support member and each side of the ejector plate at a point 41 midway along its vertical height. The chain provides a positive limit for pivotal motion of the ejector plate although the hydraulic jack alone could perform this function. A mechanical stop 42 is disposed on either side of the scraper framework 13 to act against the ejector plate and cause it to assume a vertical position when it is fully retracted to the rear of the scraper bowl by the hydraulic jack 28. The double-acting hydraulic jack 28 is pivotally connected to the ejector plate at a point 43 generally adjacent its base and to a rearward portion 44 of the scraper framework by a connection 45. A forward ejector stop 46 is disposed on the inside of each bowl sidewall 16 and acts against the ejector plate generally adjacent its pivotal connection with the ejector carriage such that continued extension of the hydraulic jacks 28 will cause the ejector plate to again assume a vertical position, indicated at 47 in the drawing, upon completion of the forward traversal of the bowl by the ejector plate.

In operation, when the ejector plate is retracted to the rear of the scraper bowl in its normal loading position, it is in a Vertical position by means of its contact with the rearstops 42 and thus provides additional loadcarrying capacity near the floor of the bowl. This not only permits easier loading of material into that additional load-carrying space but also, since it is near the bowl oor, increases the stability of the loaded scraper. As the ejector plate and ejector carriage are driven in forward traversal of the scraper bowl by extension of the hydraulic jack 28, two particular advantages of the present invention may 'be noted. First, since motion of the ejector plate is resisted by material in the scraper bowl, the ejector plate is pivoted rearwardly into a position where it rests upon support member 36 during its forward traversal. Thus, the ejector plate is caused to assume a preselected angle in the bowl which prevents its tendency of riding up and over the material in the bowl. Further, since forward motion of the ejector plate is resisted by the material, its pivoted connection with the ejector carriage and the action of the hydraulic jack adjacent the base of the ejector plate cause an initial forward traversal of the bowl by the lower portion of the ejector plate prior to any substantial forward mo-tion in the upper portion of the ejector plate. Since the peak force to be exerted on the load by the ejector plate occurs during this initial traversing motion, due to the requirement of setting the load in motion, the present embodiment has the advantage of rst setting the lower portion of the load in motion and then the upper portion of the load to reduce the peak force to be exerted through the ejector plate upon the load. Although the present invention is not described with respect to a self-loading scraper, it may be noted that when the present ejector is employed in a self-loading scraper having an elevator, this pivoting motion of the ejector plate during its initial traversal of the bowl would tend to eliminate bridging of material between an upper portion of the ejector plate and the elevator due to the lower portion of the load being moved toward a position for ejection from the bowl prior to any substantial motion in the upper portion of the load.

As the forward traversal of the bowl by the ejector plate is completed according to extension of the hydraulic jack 28, the base of the ejector plate comes into contact with the forward mechanical stops 46. Since the stops are below the connection of the hydraulic jack with the ejector plate, the ejector plate will tend to assume a vertical position as it contacts the stops. The scraper operator may employ this action of the ejector plate against the forward stops to shake sticky material from the face of the ejector plate.

What is claimed is:

1, An ejector assembly for an earthmoving scraper having a bowl and bowl floor, comprising an ejector carriage disposed adjacent the bowl floor,

an ejector plate pivoted at its base to the carriage,

ymotor means associated with the ejector plate and carriage for moving the ejector plate between a Crt loading position at the rear of the ybowl and an unloading position at the front of the bowl, said motor means comprising a hydraulic jack interconnected between a portion of the scraper structure and the ejector plate at a position above the pivotal connection between the ejector plate and carriage,

stop means at the rear of the bowl for interacting with the ejector plate and causing it to assume a generally vertical loading position,

means mounted on the carriage for supporting the ejector plate in a rearwardly and upwardly inclined position during unloading of the bowl, and

stop means at the forward end of the bowl for interacting with the ejector plate below its interconnection to the hydraulic jack, said stop means at the forward end of the bowl limiting forward motion of the bottom of the ejector plate as it approaches the forward end of the bowl to cause the plate to assume a generally vertical position.

2. An ejector assembly for an earthmoving scraper having a bowl and bowl tloor, comprising an ejector carriage disposed adjacent the bowl oor,

an ejector plate pivoted at its base to the carriage,

motor means associated with the ejector plate and carriage for moving the ejector plate between a loading position at the rear of the bowl and an unloading position at the front of the bowl,

stop means at the rear of the bowl for interacting with the ejector plate and causing it to assume a generally vertical loading position,

means mounted on the carriage for supporting the ejector plate in a rearwardly and upwardly inclined position during unloading of the bowl, and

ilexible means interconnected between the ejector plate and carriage, the flexible means permitting the ejector plate to freely pivot between its generally vertical position and its rearwardly and upwardly inclined position during movement between its loading and unloading positions.

References Cited UNITED STATES PATENTS 2,226,859 12/1940 French 37-126 3,274,711 9/1966 Johnson et al 37-129 3,325,925 6/1967 Hcrmiz et al. 2:7*124 EDGAR S. BURR, Primary Examiner 

